#include<stdio.h>
#include<pthread.h>
#include<unistd.h>

int tickets = 1000;

pthread_mutex_t mutex;
void* TicketCal(void* arg)
{
  const char* name = (char*)arg;
  while(1)
  {
    pthread_mutex_lock(&mutex);
    if(tickets>0)
    {
      usleep(10000);
      printf("[%s] get a ticket, left: %d\n",name, --tickets);
      pthread_mutex_unlock(&mutex);
    }
    else 
    {
      pthread_mutex_unlock(&mutex);
      break;
    }
  }
  printf("%s quit!!!\n",name);
  pthread_exit((void*)0);
}

int main()
{
  pthread_mutex_init(&mutex,NULL);
  pthread_t t1,t2,t3,t4;
  pthread_create(&t1, NULL, TicketCal,(void*)"thread 1");
  pthread_create(&t2, NULL, TicketCal,(void*)"thread 2");
  pthread_create(&t3, NULL, TicketCal,(void*)"thread 3");
  pthread_create(&t4, NULL, TicketCal,(void*)"thread 4");
  
  pthread_join(t1,NULL);
  pthread_join(t2,NULL);
  pthread_join(t3,NULL);
  pthread_join(t4,NULL);
  pthread_mutex_destroy(&mutex);
  return 0;
}
